The synthetic Sakha-6,whicn is a new whHe maize cultlvar. was used 10
utilize its genetic variability to Imp/ove yielding potentiality through out three cycles C-
O. C-1 and C·2 of modifleO ear- to row ,METR .setectico method .The research W<3S
mace ,during 2001,2002 and 2003 growing seasons at sakna Research Stalio(\
under two nitrogen levels. The mean values for all trails, except sllklng data were
higher at the high nitrogen level 01 120 Kg NIF ad than the low nitrogen level of 70 Kg
NiF ad in the three cycles of selection. Over Iha two nitrogen levels, the mean of cycle-
2 was higher than cycle-O for grain yield, ssr length and ear diameter, while it was the
reverse lor silklng date, plant and ear heights. These results Indicated that the
modi ned ear-to-row selection method were ertecuve fo( IncreasIng grain yield and
yield components and in decreasing sllking date and plan I and ear heights Genetic
variance W<3S significant al the two nilf099f1 levels and theil combined for all traits in
most three cycles of METR selection methods. The Interactions between genetic
variance and nitrogen levels were {\Qt significanl for all (rails In the three cycles.
Moreover, the phenotypic and genotypic variances. over the rv.-o nitrogen fevels, were
low at C-2 than G-O lor all trails except phenotypic variance lor silking date. Broad
sense hertiabllity H\% values were hlgner under the high nitrogen level than the low
nitrogen level for au traits at the three cycles. However, the herilabitity estimates. over
the two nitrogen levels, decreased from C·O 10 C2 in MCTR selection rnetbod for all
traits. H~~~/. for grain yield was 75_5%. 48.3% and 18.9% at C-O,C-1 aM C-2,
respectively. This Indicated that g&nelic variability was decreased with the advances
of cycles 01 selection. The expected gain lrom selection was higher under h:gh
nitrogen level than low nillogcn level for sllking dale. plant height and gral(\ yield 1(\
two out of Ihe three cycles. The expected genetic advance lrom selection lIG% for all
traits were low at G-2 than C"() over the two nitrogen levels. L\G% (or grain yieto wele
139%.10.0\% and 3.14% at C-O.C·l and G-2. respectively. Moreover, the h;ghest
values lor expected gain from selection at the two nilrogen levers and when combined
were obtained for grain yield compared with other traits In each cycle.